Variable capacity pump for governing apparatus



Sept. 30, 1941. M. GOTITLIVVEB VARIABLE CAPACITY PUMP FOR GOVERNING APPARATUS Filed Jan. 4, 1940 a Wm J n m .m w m 0 6 4 o v W 0 7 M 4 2 w & ii. I \a \,r anu m 1 ILI V Patented Sept. 30, 1941 VARIABLE CAPACITY PUMP FOR GOVERNING APPARATUS Manious Gottlieb, Philadelphia, Pa., assignor to Westinghouse Electric at Manufacturing Company, East Pittsburgh, Pa, a corporation of Pennsylvania Application January 4, 1940, Serial No. 312,320

4 Claims My invention relates to a Pump for supplyin oil for governing or control purposes for apparatus, for example, a steam turbine, operative over a relatively wide speed range and it has for an object to provide a pump capable of supplying the quantity of oil required at all Speeds without pumping an excessive amount at high speeds.

Pumps are commonly employed to furnish oil for steam turbine hydraulic governing systems. As such a pump is driven at a fixed ratio with respect to the turbine speed, it there is a wide speed range and the pump is adequate at the lowest speed, an excessive amount of oil willbe pumped at the highest speed. For example, where a steam turbine is used to drive a paper mill, 9. wide speed range is required. Assuming, for such use, a 12 to 1 speed range and a pump large enough to supply the necessary amount of oil at the lowest speed, then the pump would supply twelve times the amount required at the highest speed and this would involve oversize piping and unnecessary power loss on account of excessive pumping capacity at high speed. Accordingly, it is a further object of this invention to provide a main oil pump large enough to supply the necessary amount oi! oil for low speed and still not pump a proportionately large amount at high speed. 4 r

. A further object 01! the invention is to provide a gear pump comprising a gear meshing with a multiplicity of pinions to constitute a plurality of gear pumpunits, one of which is at all times effective and the other or othersoi which are rendered efiective at the slower speeds to give the increased amount of oil required.

A further object of the invention is to provide a pump for a governor system of a prime mover having a wide speed range and comprising a multiplicity of gear pump units, one of such units be- In Fig. 1, there is shown an elastic-fluid turbine l having bearings 2 for a spindle or shaft 3 and an admission valve 4 dontrolled by a servomotor 5 operated by means of a governing system. While any suitablegove'rning system may be employed for this purpose, I prefer to use one of the pressure-transformer type such as shown, for example, in the patent to Schwendner No. 2,009,417, granted July 30, 1935, or in my application, Serial No. 260,478, filed March 8, 1939,

the transformed oil pressure being used to control the servo-motor. As shown, the transformer,

at 6, furnishes oil under transformed pressure to the servo-motor to control the operation of the latter. The transformer is controlled by a force or pressure which variesv as the square ofthespeed of the turbine, and, by way oi! example, the turbine shaft 3 is shown as driving thempeller '1 to provide such a, pressure. The governor transformer 6 has a speed changer including the rotatable adjusting member 8. The member 0' is turned to vary the force of the governor load spring and in consequence of this, the speed setting of the governor is changed.

Adequate provision -must be made for meeting the motive oil requirements or the servo-motor I as well as lubricating oil requirements or the v bearings 2 for a widespeed range of the turbine. Accordingly,' the turbine shaft 3 is shown as driving the improved pump, at l0, forthis-purpose.

The pump, at l0, includes a housing structure I0 enclosing the meshing gear members to provide the pumping units. For example, there is shown a gear ll driven from the shait 3 and meshing with a pinion l2 to. provide a first pumping unit, at l3,-and with a pinion H to-provide a second pumping unit, at l5.

ing continuously eflective and the others being eh'ectlve at the lower speeds, together with valve -means for rendering said other pump unit or units eiiective or ineffective and operated by the speed changer or the governing system.

These and other objects are effected by my invention as will be apparent irom the following description and claims taken in accordance with the accompanying drawing, forming a part of this application, in which: 7 a

Fig. .l'is a diagrammatic view showing the improved pump applied to the governing and lubricating system or a turbine; and

Fig. 2 is a diagrammatic sectional view 01 the improved pumping apparatus.

Suction and. discharge lines 16 and; H are connected to the housing lo' the suction line being connected to any suitable source of oil, for example, to the return r drainage system for the servo-motor and the bearings, and the pump discharge line if being arranged to supply oil for motivation of the servo-motor 5 and for'lubri- .-cation of the bearings 2.

connecting the chambers 2| and 22 to the suction and discharge lines I6 and I1, respectively,

the valve member 3!.

and, with a by-pass passage 21. The suction passage 25 includes portions 28 and 29 for a purpose to be immediately described.

The housing It is formed with a valve cylinder 30 in communication with said suction passage portions 28 and 29 and with the by-pass passage 21. A piston valve 3| fits the cylinder and it is so constructed that, in one extreme position, (the left-hand position being shown) the cuited, its suction and discharge chambers 2i and 22 being directly connected. Any suitable means may be used to shift the valve 3|, and preferably such means is cooperatively related to the prime mover speed changer adjusting element 8 so that both pumping units are effective at low speeds and,only the unit, at I3, is effective at high speeds.

By way of example, hydraulic means for shifting the valve 3|, is shown, such means comprising a valve housing 34 connectedtby supply and discharge passages 35 and 36 to the cylinders 31 and 58, provided by end portions of the valve cylinder 30, for pistons 39 and 40 at the ends of connected tothe pressure supply line 42 and it 1 I has drain ports 43 and 44.

A piston valve 45 'in the valve housing is so constructed that, in one position, the pressure supply passage 42 i pla'ced'in' communication with one of the passages 35 or 35 to furnish oil under pressure to the corresponding cylinder 31 or 38 andto place the other cylinder in communication with the drain and vice versa,

whereby, as the valve 45 is moved to its extreme positions fluid is supplied to and exhausted from The valve housing, 34 is changer mechanism, it is',preferably provided with a cam device 51 arranged in the path of movement of the finger 58 attached to a rotary part of the speed changer.

From the foregoing, it will be apparent that the suction and discharge chambers of'the first pump unit are at all times connected to the suction and discharge lines, whereas the suction chamber of the second pump unit may be connected .to the suction line, in which case, the second pump unit will operate in parallel with the first, or it may be connected to its discharge chamber, whereby the second pump unit is rendered ineffective or is short-circuited. If the speed range, is sufliciently great, it will be apparentthat more than one second pumpunit may be employed, it being merely necessary to provide suitable valve mechanism for rendering each such pump unit effective and ineffective and to correlate the valve mechanisms to the y speed changer to secure proper sequence Of operation, the pump having maximum capacity at the slowest speed and minimum capacity at the highest speed.

the cylinders 31 and 38 to secure movement of I the valve 3| to its extreme positions.-

Preferably, the piston valve has lands 46,

41 and 48rfittin g the bore of the housing 34 and spaced apart by the annular channels and 50.

The lands 46 and 48 have axial bores 5| and 52 opening through ports 53 and 54 to the channels 49 and 50, respectively. 7

In the intermediate position of the piston valve 45, as'illus'trated, theintermediate land 41. laps the end of the pressure supply passage 42,

movement to thev right-places the pressure supply passage 42 in communication with the-annular channel 49 to supply fluid under pressure to the left-hand cylinder 31 and places the anrocker carried by the housing 54 andihaving an inwardly-extending projection 56 engageable with the valve to shift the latter. Where the rocker is actuated by means of the speed While I have shownmy invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire,

therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In ahydraulic governing system for a' prime mover having a wide speed range, a pump driven said source, means including a valve for connect-' 'ing the suction side or sides of the remaining pumping unit or units either to the source or to the discharge'side or sides of such remaining pumping unit or units, and means dependent upon prime mover speed for operating the valve such that, at the maximum speed, said remaining pumping unit or units are disconnected from said source and, at minimum speed, they are connected thereto.

2. In a hydraulic governing system for a prime mover having a wide speedrange and provided .with. a speed changer, a pump for furnishing oil for the system and comprising a gear meshing with a plurality of pinions to,provide a multiplicity of gear pumping units, means providing an oil supply source, a discharge passage for supplying oil under pressure from the pumping units to the system, means for continuouslyconnecting the discharge sides of all of the pumping units to the discharge passage and continuously connecting the suction'side of one of the pumping units to said source, means including a valve for connecting the suction side or sides of the' remaining pumping unit or units either to said source or to the discharge side or sides. thereof, and means providing for'operation of the valve by said speed changerin order that, at the maximum prime mover speed, said remaining pumping unit or units are disconnectedfrom said source and.

at the minimum prime mover speed, they are connected thereto.

3. In a hydraulic governing system for a prime mover having a wide speed range and provided with a speed changer, a pump for furnishing oil for the system and comprising a gear, a pair or pinions to provide 'flrst and second pumping units; suction and discharge lines; a housing for the pumping'units and provided with suction and discharge chambers for the units; said housing having passages connecting said suction and dissuction and discharge chambers for the units;

- its suction passage, with the suction line, and, to

charge chambers to the suction and discharge 3 lines, respectively, and a by-pass passage communicating with the discharge chamber oi said second pumping unit; a slide valve movable to a first position, to establish communication of the suction chamber of the second pumping unit, through its suction passage, with the suction line, and, to a second position, to interrupt such communication and'establish communication of the suction and discharge chambers of the second unit by means of the by-pass passage; and means providing for movement of the slide valve by the speed changer.

4. In a hydraulic governing system for a prime mover having a wide speed range and provided with a speed changer, a pump for furnishing oil tor the system and comprising a gear meshing with a pair of pinions to provide first and second pumping units; suction and discharge lines; a

housing for the pumping and provided with a second position, to interrupt such communication and to establish communication of the suction and discharge chambers of the second unit by means of the by-pass: and means for shifting the slide valve including pistons connected to the ends of the latter, cylinders for the pistons, a valve housing having drain ports, supply and exhaust passages connected to the cylinders and to the valve housing, a pressure conduit connected to the valve housing, a valve in the valve housing and movable to a first position, placing-one supply and exhaust passage in communication with the pressure conduit and placing the other supply and exhaust passage in communication with a drain port, and, movable to a second position, placing said other supply and exhaust passage in communication with the pressure conduit and the iirst supply and exhaust passage in communication with the drain'port, and means operated by the speed changer for shifting said valve.

MANIOUS GO'I'ILIEB. 

